Abstract
Abstract It has been shown long ago experimentally that primary nucleation of dislocations in silicon takes place heterogeneously on defects along the crack tip. More recently, it has been observed that a source is easily activated at the intersection point of the crack front and of an attracted dislocation. The authors offer and discuss a source multiplication mechanism based on this stimulated emission process. One of the dislocations emitted at a primary source on the plane of maximum resolved shear stress cross-slips to a plane where it is attracted by the crack: the intersection event gives rise to a secondary source. Because shielding is very low at this point, there occurs an emission of a new bundle of dislocations. The process then starts again giving rise to an ‘avalanche multiplication’ of dislocations which strongly shield the crack. Soft/sharp brittle to ductile transitions (BDT) observed in semi-brittle materials result from such a high shielding rate coupled with a low/high threshold stress intensity factor for the activation of the primary sources.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
